Abstract
Diffusion is a natural phenomenon and essential in many fields. Conceptually, diffusion in solid materials, especially in the confined micro/nano-spaces, can boost the development of new functional nanomaterials for applications across a range of areas. In this Minireview, we categorize the diffusion behavior at the nanoscale including atom/ion diffusion and direct migration of nanoparticles, and discuss how these two strategies can be applied for the construction of nanoreactors with unique structures and components. The understanding of diffusion principles in a confined system is summarized in detail. Moreover, the development opportunities of diffusion process in future research are outlined.